As bearings capable of realizing ultra low friction, ultra high precision, and ultra high-speed motion, hydrostatic gas bearings are used in applications such as the conveyance of articles and ultra precision processing and ultra precision measurement by moving articles horizontally. The types of air outlet ports of this hydrostatic gas bearing include such as a porous restrictor, a surface restrictor, an orifice restrictor, and an inherent restrictor, and are respectively used depending on applications while adjusting the load capacity, the bearing rigidity, and the like.
As a gas bearing system which realizes higher damping while maintaining relatively high stiffness, a gas bearing system is proposed in Patent Document 1, for example, which comprises two opposing substantially parallel bearing surfaces and at least one gas duct for supplying gas through an orifice to a bearing gap between the bearing surfaces.
In addition, Patent Document 2 proposes a hydrostatic gas bearing which comprises: a base material constituted of a porous body; and a surface restrictor layer joined on this base material and constituted of a porous plate fabricated by adjusting the diameter and distribution of through holes so as to obtain a desired air permeation rate in advance, wherein gas is blown out through the surface restrictor layer so as to support a supported member by its static pressure.